Methods for reducing aldehyde emissions in polyurethane foams

ABSTRACT

Polyurethane foams are made by curing a reaction mixture that contains an aromatic polyisocyanate, at least one isocyanate-reactive material having an average functionality of at least 2 and an equivalent weight of at least 200 per isocyanate-reactive group, at least one blowing agent, at least one surfactant and at least one catalyst, at least one acetoacetate ester or amide and at least one aminoalcohol or alkylhydroxylamine. Foams so produced emit low levels of formaldehyde, acetaldehyde and propionaldehyde.

This invention relates to polyurethanes that exhibit low levels ofaldehyde emissions, and to methods for producing such polyurethanes.Polyurethane foams are used in many office, household and vehicularapplications.

They are used, for example, in appliance applications and as cushioningfor bedding and furniture. In automobiles and trucks, polyurethanes areused as seat cushioning, in headrests, in dashboards and instrumentpanels, in armrests, in headliners, and other applications.

These polyurethanes often emit varying levels of aldehydes such asformaldehyde, acetaldehyde and propionaldehyde. Because of the cellularstructure of these foams, aldehydes contained in the foam easily escapeinto the atmosphere. This can present an odor concern and an exposureconcern, especially when people or animals are exposed to the materialwithin an enclosed space. Vehicle manufacturers are imposing stricterlimits on the emissions from materials that are used in the passengercabins of cars, trucks, trains and aircraft.

Scavengers are sometimes used to reduce aldehyde emissions from varioustypes of materials. In the polyurethane field, there is, for example, WO2006/111492, which describes adding antioxidants and hindered aminelight stabilizers (HALS) to polyols to reduce aldehydes. WO 2009/114329describes treating polyols with certain types of aminoalcohols andtreating polyisocyanates with certain nitroalkanes, in order to reducealdehydes in the polyols and polyisocyanates, respectively, and inpolyurethanes made from those materials. JP 2005-154599 describes theaddition of an alkali metal borohydride to a polyurethane formulationfor that purpose. U.S. Pat. No. 5,506,329 describes the use of certainaldimine oxazolidine compounds for scavenging formaldehyde frompolyisocyanate-containing preparations, and describes nitroalkanes andaminoalcohols as formaldehyde scavengers in textile and plywoodapplications.

These approaches provide limited benefit, in part because aldehydespresent in polyurethane foam are not always carried in from the rawmaterials used to make the foam. Formaldehyde and acetaldehyde inparticular can form during the curing step or when the foam is latersubjected to UV light, elevated temperatures or other conditions. Inaddition, measures that are effective against formaldehyde emissions arenot always effective against acetaldehyde or propionaldehyde emissions,and vice versa. In some cases, measures that are effective in reducingacetaldehyde emissions can actually cause an increase in formaldehydeemissions. Applicants have further found that the presence of HALS oftenleads to an increase in formaldehyde emissions, acetaldehyde emissionsor both.

PCT/CN2017/073764 describes the use of aminoalcohols together withcertain antioxidants to reduce aldehyde emissions from polyurethanefoam. This combination provides some improvement, but a greaterreduction of aldehyde emissions is wanted. Therefore, a method foreffectively and economically reducing formaldehyde, acetaldehyde andpropionaldehyde emissions is wanted. Preferably, this method does notresult in a significant change in the properties or performance of thepolyurethane.

This invention is a process for producing a polyurethane foam comprisingforming a reaction mixture that contains an aromatic polyisocyanate, atleast one isocyanate-reactive material having an average functionalityof at least 2 and an equivalent weight of at least 200 perisocyanate-reactive group, at least one blowing agent, at least onesurfactant and at least one catalyst, and curing the reaction mixture inthe presence of (i) at least one acetoacetate ester or amide and (ii) atleast one aminoalcohol and/or alkylhydroxylamine, to form thepolyurethane foam. The invention is also a process for reducing aldehydeemissions from a polyurethane foam, comprising: a) combining (i) atleast one acetoacetate ester or amide and (ii) at least one aminoalcoholand/or alkylhydroxylamine with at least one isocyanate-reactive materialhaving an average functionality of at least 2 and an equivalent weightof at least 200 per isocyanate-reactive group to form a mixture and thenb) combining the mixture from step a) with at least one organicpolyisocyanate and curing the resulting reaction mixture in the presenceof at least one blowing agent, at least one surfactant and at least onecatalyst to form a polyurethane foam.

The invention is also a polyurethane foam made in either of theforegoing processes. The combination of the acetoacetate ester or amideand aminoalcohol and/or hydroxylamine has been found to reduce thelevels of each of formaldehyde, acetaldehyde and propionaldehyde emittedby the polyurethane foam.

To produce foam in accordance with the invention, at least onepolyisocyanate is reacted with at least one isocyanate-reactive compoundthat has a functionality of at least 2 and an equivalent weight of atleast 200 per isocyanate-reactive group. Other ingredients may bepresent as discussed hereinbelow. The reaction is performed in thepresence of the acetoacetate ester or amide and the aminoalcohol and/orhydroxylamine.

The acetoacetate ester or amide and aminoalcohol and/or hydroxylaminecan be provided as a mixture with any one or more of the variousingredients of the formulation used to produce the foam. Alternatively,these may be added into the reaction as a separate component or streamwithout being previously combined with any of the other ingredients.

Preferably, however, the acetoacetate ester or amide and aminoalcoholand/or hydroxylamine are blended with the isocyanate reactivecompound(s) that have at least two isocyanate-reactive groups permolecule and an equivalent weight of at least 200 perisocyanate-reactive group, prior to forming the polyurethane foam. Theresulting blend is maintained at approximately room temperature or ahigher temperature (but below the boiling temperature of theacetoacetate ester or amide and the aminoalcohol and/or hydroxylamineand below the temperature at which the polyol degrades) for a period ofat least 30 minutes prior to making the foam. Such a blend may bemaintained under such conditions for any arbitrarily longer time, suchas up to a month, up to a week, or up to a day.

The acetoacetate ester or amide is characterized by having one or moreacetoacetate ester or acetoacetate amide groups having structure I:

wherein R¹ is a substituted or unsubstituted C₁-C₆ alkyl or asubstituted or unsubstituted aryl group, preferably a C₁ or C₂ alkylgroup and X is —O— in the case of an ester and —NH—, in the case of anamide. R¹ is most preferably methyl. The acetoacetate ester or amide mayhave two or more such acetoacetate ester or amide groups. Among thesuitable acetoacetate esters are those represented by structure II:

wherein A is a linking group, n is at least 1 and R¹ and X are asdescribed with regard to structure I. A may be, for example, a C₁-C₃₀linear or branched alkyl, aryl, arylalkyl, alkaryl group, wherein thesubstituents may be or include or more of O, N, S, P or halogen.Oxygen-containing substituents may be, for example, carbonyl, hydroxyl,ester, carbonate or ether groups. n may be, for example, 1 to 100, 1 to20, 1 to 10 or 1 to 4. n is preferably at least 2 when X is oxygen.

Useful acetoacetate compounds include those described in JP 2005-06754A,JP 2005- 179423A and US Publication No. 2016/0304686, all of which areincorporated by reference herein in its entirety.

In some embodiments, X in structure II is oxygen, n is at least 2 and Ais the residue of a polyalcohol after removal of one or more —OH groups.The acetoacetate compound in such a case is an acetoacetate ester orpolyester of an alcohol having the form A(OH), where x is equal to orgreater than n. Examples of acetoacetate esters include mono- andpolyacetoacetate esters of polyols such as ethylene glycol,1,2-propylene glycol, 1,3- propylene glycol, 1,4-butane diol, 1,6-hexanediol, glycerin, trimethylolpropane, trimethylolethane,trimethoxymethane, erythritol, pentaerythritol, diethylene glycol,triethylene glycol, dipropylene glycol, tripropylene glycol, sorbitol,mannitol, glucose, fructose, sucrose, 1,2,3,4,5,6-hexahydroxy-n-hexane,and the like.

Specific acetoacetate ester compounds include, for example,trimethylolpropane z o mono-, di or triacetoacetate ester,trimethylolethane mono-, di- or tri acetoacetate ester,trimethoxymethane mono-, di- or triacetoacetate ester; ethylene glycolmono- or diacetoacetate ester; 1,2-propylene glycol mono- ordiacetoacetate ester, 1,3-propylene glycol mono- or diacetoacetateester, pentaerythritol mono-, di-, tri- or tetraacetoacetate ester,glycerin mono-, di or triacetoacetate ester, diethylene glycol mono- ordiacetoacetate ester, dipropylene glycol mono- or diacetoacetate ester,triethylene glycol mono- or diacetoacetate ester, erythritol mono-, di-,tri- or tetraacetoacetate ester, n-hexane mono-, di, tri, tetra, penta-,or hexaacetoacetate ester, sorbitol mono-, di-, tri-,tetra-, penta- orhexaacetoacetate ester and 1,4-butanediol mono- or diacetoacetate ester.

In some embodiments, X in structure II is —NH—, n is one or more and Ais the residue of an amine or polyamine after removal of one or more—NH₂ groups. The acetoacetate compound in such a case is an acetoacetateamide or polyamide of an amine having the form A(NH₂)_(x), where x isequal to or greater than n. An example of such an amide compound is

A suitable amount of acetoacetate ester or amide is from 0.01 to 1 pph(i.e., 0.01 to 1 parts by weight per 100 parts by weight of isocyanatereactive compound(s) that have at least two isocyanate-reactive groupsper molecule and an equivalent weight of at least 200 perisocyanate-reactive group). The amount of cyclic 1,3-diketone compoundmay be at least 0.02, at least 0.03 pph or at least 0.04 pph and may beup to 0.5 pph, up to 0.35 pph, up to 0.25 pph or up to 0.15 pph.

Aminoalcohol compounds are characterized in having at least one primaryor secondary amino group and at least one hydroxyl group, each beingbonded to an aliphatic carbon atom. In some embodiments, a hydroxylgroup is bonded to a carbon in the alpha position relative to the carbonatom to which a primary or secondary amino group is bonded. Analkylhydroxylamine includes an —NH—OH group wherein the nitrogen atom isbonded to an aliphatic carbon atom.

Aminoalcohol compounds are known and include for example, thosedescribed in US Publication Nos. 2009/0227758 and 2010/0124524, each ofwhich are incorporated herein in their entirety.

In some embodiments, the aminoalcohol or alkylhydroxylamine compound isa compound represented by structure III:

or a salt of such a compound, wherein

R⁶, R⁷ and R⁸ each are independently H, alkyl optionally substitutedwith phenyl or NR⁹R¹⁰ wherein R⁹ and R¹⁰ are independently H, C₁-C₆alkyl, phenyl, or hydroxyalkyl optionally independently substituted withphenyl or NR⁹R¹⁰;

R⁵ is H, hydroxyl, phenyl, alkyl optionally substituted with phenyl orNR⁹R¹⁰, or hydroxyalkyl optionally independently substituted with phenylor NR⁹R¹⁰, provided that when none of R⁶, R⁷ and R⁸ are hydroxyalkyl,then R⁵ is hydroxyl or hydroxyalkyl optionally independently substitutedwith phenyl or NR⁹R¹⁰.

Specific examples of suitable aminoalcohols are 2-amino-1-butanol,2-amino-2-ethyl-1, 3-propanediol, 2-amino-2-methyl-1-propanol,2-amino-1-methyl-1,3-propanediol, 1,1,1-tris (hydroxymethyl)methylamine, ethanolamine, diethanolamine, N-methylethanolamine,N-butylethanolamine, monoisopropanolamine,2-amino-2(hydroxymethyl)propane-1,3-diol. diisopropanolamine,mono-sec-butanolamine, di-sec-butanolamine, or salts thereof. Theseaminoalcohols are available from a variety of commercial sources,including ANGUS Chemical Company (Buffalo Grove, Ill., USA), The DowChemical Company (Midland, Mich., USA), or can be readily prepared bytechniques well known in the art. The aminoalcohols can be used in theform of salts. Suitable salts include hydrochloride, acetate, formate,oxalate, citrate, carbonate, sulfate, and phosphate salts.

Specific examples of alkylhydroxylamines includeN-isopropylhydroxylamine, N-ethylhydroxylamine, N-methylhydroxylamine,N-(n-butyl)hydroxylamine, N-(sec-butyl)hydroxylamine and the like.

A suitable amount of aminoalcohol and/or alkylhydroxylamine compound isfrom 0.01 to 5 pph. The amount of aminoalcohol and/or alkylhydroxylaminecompound may be at least 0.025, at least 0.05 pph or at least 0.075 pphand may be up to 2 pph, up to 1 pph, up to 0.5 pph, up to 0.25 pph or upto 0.2 pph. The foam formulation includes at least oneisocyanate-reactive compound that has a functionality of at least 2 andan equivalent weight of at least 200 per isocyanate-reactive group.“Functionality” refers to the average number of isocyanate-reactivegroups per molecule. The functionality may be as much as 8 or more butpreferably is from 2 to 4. The isocyanate groups may be, for example,hydroxyl, primary amino or secondary amino groups, but hydroxyl groupsare preferred. The equivalent weight may be up to 6000 or more, but ispreferably from 500 to 3000 and more preferably from 1000 to 2000. Thisisocyanate-reactive compound may be, for example, a polyether polyol, apolyester polyol, a hydroxyl-terminated butadiene polymer or copolymer,a hydroxyl-containing acrylate polymer, and the like. A preferred typeof isocyanate-reactive compound is a polyether polyol, especially apolymer of propylene oxide or a copolymer of propylene oxide andethylene oxide. A copolymer of propylene oxide and ethylene oxide may bea block copolymer having terminal poly(oxyethylene) blocks and in whichat least 50% of the hydroxyl groups are primary. Another suitablecopolymer of propylene oxide and ethylene oxide may be a random orpseudo-random copolymer, which may also contain terminalpoly(oxyethylene) blocks and in which at least 50% of the hydroxylgroups are primary.

Polyester polyols that are useful as the isocyanate-reactive compoundinclude reaction products of polyols, preferably diols, withpolycarboxylic acids or their anhydrides, preferably dicarboxylic acidsor dicarboxylic acid anhydrides. The polycarboxylic acids or anhydridesmay be aliphatic, cycloaliphatic, aromatic and/or heterocyclic and maybe substituted, such as with halogen atoms. The polycarboxylic acids maybe unsaturated. Examples of these polycarboxylic acids include succinicacid, adipic acid, terephthalic acid, isophthalic acid, trimelliticanhydride, phthalic anhydride, maleic acid, maleic acid o anhydride andfumaric acid. The polyols used in making the polyester polyolspreferably have an equivalent weight of about 150 or less and includeethylene glycol, 1,2- and 1,3-propylene glycol, 1,4- and 1,3-butanediol, 1,6-hexane diol, 1,8-octane diol, neopentyl glycol, cyclohexanedimethanol, 2-methyl-1,3-propane diol, glycerine, trimethylolpropane,1,2,6-hexane triol, 1,2,4-butane triol, trimethylolethane,pentaerythritol, quinitol, mannitol, sorbitol, methyl glycoside,diethylene glycol, triethylene glycol, tetraethylene glycol, dipropyleneglycol, dibutylene glycol and the like. Polycaprolactone polyols such asthose sold by The Dow Chemical Company under the trade name “Tone” arealso useful.

Mixtures of two or more of the foregoing isocyanate-reactive compoundshaving a functionality of at least 2 and an equivalent weight of atleast 200 per isocyanate-reactive group can be used if desired.

The isocyanate-reactive compound(s) may contain dispersed polymerparticles. These so-called polymer polyols contain, for example,particles of vinyl polymers such as styrene, acrylonitrile orstyrene-acrylonitrile, particles of a polyurea polymer, or polymers of apolyurethane-urea polymer.

In addition, such isocyanate-reactive compounds can be used in admixturewith one or more crosslinkers and/or chain extenders. For purposes ofthis specification, “crosslinkers” are compounds having at least threeisocyanate-reactive groups per molecule and an equivalent weight perisocyanate-reactive group of below 200. “Chain extenders” for purposesof this invention have exactly two isocyanate-reactive groups permolecule and have an equivalent weight per isocyanate-reactive group ofbelow 200. In each case, the isocyanate-reactive groups are preferablyhydroxyl, primary amino or secondary amino groups. Crosslinkers andchain extenders preferably have equivalent weights of up to 150 and morepreferably up to about 125.

Examples of crosslinkers include glycerin, trimethylolpropane,trimethylolethane, diethanolamine, triethanolamine, triisopropanolamine,alkoxylates of any of the foregoing that have equivalent weights of upto 199, and the like. Examples of chain extenders include alkyleneglycols (e.g., ethylene glycol, propylene glycol, 1,4-butane diol, 1,6-s hexanediol and the like), glycol ethers (such as diethylene glycol,triethylene glycol, dipropylene glycol, tripropylene glycol and thelike), ethylene diamine, toluene diamine, diethyltoluene diamine and thelike, as well as alkoxylates of any of the foregoing that haveequivalent weights of up to 199, and the like.

Crosslinkers and/or chain extenders are typically present in smallamounts (if at all). A preferred amount is from 0 to 5 pph ofcrosslinkers and/or chain extenders. A more preferred amount is from0.05 to 2 pph and a still more preferred amount is from 0.1 to 1 pph ofone or more crosslinkers.

Examples of suitable polyisocyanates include, for example, m-phenylenediisocyanate, 2,4- and/or 2,6-toluene diisocyanate (TDI), the variousisomers of diphenylmethanediisocyanate (MDI), the so-called polymericMDI products (which are a mixture of polymethylene polyphenylenepolyisocyanates in monomeric MDI), carbodiimide- modified MDI products(such as the so-called “liquid MDI” products which have an isocyanateequivalent weight in the range of 135-170),hexamethylene-1,6-diisocyanate, tetramethylene-1,4-diisocyanate,cyclohexane-1,4-diisocyanate, hexahydrotoluene diisocyanate,hydrogenated MDI (H₁₂MDI), isophorone diisocyanate,naphthylene-1,5-diisocyanate, methoxyphenyl-2,4-diisocyanate,4,4′-biphenylene diisocyanate, 3,3′-dimethyoxy-4,4′-biphenyldiisocyanate, 3,3′-dimethyldiphenyl methane-4,4′-diisocyanate,4,4′,4″-triphenylmethane diisocyanate, hydrogenated polymethylenepolyphenylpolyisocyanates, toluene-2,4,6-triisocyanate and4,4′-dimethyldiphenylmethane-2,2′,5,5′-tetraisocyanate. Any of theforegoing that are modified to contain urethane, urea, uretonimine,biuret, allophonate and/or carbodiimide groups may be used.

Preferred isocyanates include TDI, MDI and/or polymeric MDI, as well asderivatives of MDI and/or polymeric MDI that contain urethane, urea,uretonimine, biuret, allophonate and/or carbodiimide groups. Anespecially preferred isocyanate is a mixture of TDI and MDI.

The amount of polyisocyanate provided to the foam formulation isexpressed as the “isocyanate index”, which is 100 times the ratio ofisocyanate groups to isocyanate-reactive groups in the foam formulation.The isocyanate index is typically from about 70 to 150. A preferredisocyanate index is from 80 to 125 and a more preferred isocyanate indexis from 80 to 115. In some embodiments, the isocyanate index is from 90to 115 or from 95 to 115.

The blowing agent may be a chemical (exothermic) type, a physical(endothermic) type or a mixture of at least one of each type. Chemicaltypes typically react or decompose to produce carbon dioxide or nitrogengas under the conditions of the foaming reaction.

Water and various carbamate compounds are examples of suitable chemicalblowing agents. Physical types include carbon dioxide, variouslow-boiling hydrocarbons, hydrofluorocarbons, hydroflurochlorocarbons,ethers and the like. Water is most preferred blowing agent, either byitself or in combination with one or more physical blowing agents.

Blowing agents are present in amounts sufficient to provide the desiredfoam density. When water is the blowing agent, a suitable amount isgenerally from 1.5 to 6 pph, preferably from 2 to 5 pph.

Suitable surfactants are materials that help to stabilize the cells ofthe foaming reaction mixture until the materials have cured. A widevariety of silicone surfactants as are commonly used in makingpolyurethane foams can be used in making the foams with the polymerpolyols or dispersions of this invention. Examples of such siliconesurfactants are commercially available under the tradenames Tegostab™(Evonik Corporation), Niax™ (Momentive) and Dabco™ (Air Products andChemicals).

Surfactants are typically present in amounts up to 5 pph, more typicallyfrom 0.1 to 2 pph and preferably from 0.25 to 1.5 pph.

Suitable catalysts include those described by U.S. Pat. No. 4,390,645,which is incorporated herein by reference. Representative catalystsinclude:

-   (a) tertiary amines, such as trimethylamine, triethylamine,    N-methylmorpholine, N-ethylmorpholine, N,N-dimethylbenzylamine,    N,N-dimethylethanolamine, N,N,N′,N′-tetramethyl-1,4-butanediamine,    N,N-dimethylpiperazine, 1,4-diazobicyclo-2,2,2-octane,    bis(dimethylaminoethyl)ether, bis(2-dimethylaminoethyl) ether,    morpholine,4,4′-(oxydi-2,1- ethanediyl)bis,    tri(dimethylaminopropyl)amine, pentamethyldiethylenetriamine and    triethylenediamine and the like; as well as so-called “low emissive”    tertiary amine catalysts that contain one or more    isocyanate-reactive groups such as dimethylaminepropylamine and the    like;-   (b) tertiary phosphines, such as trialkylphosphines and    dialkylbenzylphosphines;-   (c) chelates of various metals, such as those which can be obtained    from acetylacetone, benzoylacetone, trifluoroacetyl acetone, ethyl    acetoacetate and the like with metals such as Be, Mg, Zn, Cd, Pd,    Ti, Zr, Sn, As, Bi, Cr, Mo, Mn, Fe, Co and Ni;-   (d) acidic metal salts of strong acids, such as ferric chloride,    stannic chloride, stannous chloride, antimony trichloride, bismuth    nitrate and bismuth chloride;-   (e) strong bases, such as alkali and alkaline earth metal    hydroxides, alkoxides and phenoxides;-   (f) alcoholates and phenolates of various metals, such as Ti(OR)₄,    Sn(OR)₄ and Al(OR)₃, wherein R is alkyl or aryl, and the reaction    products of the alcoholates with carboxylic acids, beta-diketones    and 2-(N,N-dialkylamino)alcohols;-   (g) salts of organic acids with a variety of metals, such as alkali    metals, alkaline earth metals, Al, Sn, Pb, Mn, Co, Ni and Cu    including, for example, sodium acetate, stannous octoate, stannous    oleate, lead octoate, metallic driers, such as manganese and cobalt    naphthenate; and-   (h) organometallic derivatives of tetravalent tin, trivalent and    pentavalent As, Sb and Bi and metal carbonyls of iron and cobalt.

Catalysts are typically present in small amounts, such as up to 2 pphand generally up to 1 pph. A preferred amount of catalyst is from 0.05to 1 pph.

It is preferred to produce the foam in the presence of at least oneantioxidant. Such an antioxidant may be blended with the isocyanatereactive compound(s) that have at least two isocyanate-reactive groupsper molecule and an equivalent weight of at least 200 perisocyanate-reactive group prior to forming the polyurethane foam, in themanner described above with regard to the cyclic 1,3-diketone,aminoalcohol and alkylhydroxylamine compounds. Alternatively, it may beadded into the reaction mixture with one or more other ingredientsand/or as a separate ingredient or stream.

Examples of suitable antioxidants include, for example:

-   1) Phenolic compounds such as 2,6-di-tert-butyl-4-methylphenol,    2-tert-butyl-4,6-dimethylphenol, 2,6-di-tert-butyl-4-ethylphenol,    2,6-di-tert-butyl-4-n-butylphenol,    2,6-di-tert-butyl-4-isobutylphenol,    2,6-dicyclopentyl-4-methylphenol,    2-(α-methylcyclohexyl)-4,6-dimethylphenol,    2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol,    2,6-di-tert-butyl-4-methoxymethylphenol, nonylphenols which are    linear or branched in the side chains, for example    2,6-di-nonyl-4-methylphenol,    2,4-dimethyl-6-(1′-methylundec-1′-yl)phenol,    2,4-dimethyl-6-(1′-methylheptadec-1′-yl)phenol,    2,4-dimethyl-6-(1′-methyltridec-1′-yl)phenol,    2,4-dioctylthiomethyl-6-tert-butylphenol,    2,4-dioctylthiomethyl-6-methylphenol,    2,4-dioctylthiomethyl-6-ethylphenol,    2,6-di-dodecylthiomethyl-4-nonylphenol,    2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butylhydroquinone,    2,5-di-tert-amylhydroquinone, 2,6-dip henyl-4-octadecyloxyphenol,    2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole,    3,5-di-tert-butyl-4-hydroxyanisole,    3,5-di-tert-butyl-4-hydroxyphenyl stearate,    bis(3,5-di-tert-butyl-4-hydroxyphenyl) adip ate,    2,2′-methylenebis(6-tert-butyl-4-methylphenol),    2,2′-methylenebis(6-tert-butyl-4-ethylphenol),    2,2′-methylenebis[4-methyl-6-(α-methylcyclohexyl)phenol],    2,2′-methylenebis(4-methyl-6-cyclohexylphenol),    2,2′-methylenebis(6-nonyl-4-methylphenol),    2,2′-methylenebis(4,6-di-tert-butylphenol),    2,2′-ethylidenebis(4,6-di-tert-butylphenol),    2,2′-ethylidenebis(6-tert-butyl-4-isobutylphenol), 2,2′-methylenebis    [6-(α-methylbenzyl)-4-nonylphenol], 2,2′-methylenebis [6-(α,    α-dimethylbenzyl)-4-nonylphenol], 4,4′-methylenebis    (2,6-di-tert-butylphenol),    4,4′-methylenebis(6-tert-butyl-2-methylphenol),    1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane, 2,6-bis    (3-tert-butyl- 5-methyl-2-hydroxybenzyl)-4-methylphenol,    1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,    1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)-3-n-dodecylmercaptobutane,    ethylene glycol    bis[3,3-bis(3′-tert-butyl-4′-hydroxyphenyl)butyrate],    bis(3-tert-butyl-4-hydroxy-5-methyl-phenyl)dicyclopentadiene, bis    [2-(3′-tert-butyl-2′-hydroxy-    5′-methylbenzyl)-6-tert-butyl-4-methylphenyl]terephthalate,    1,1-bis-(3,5-dimethyl-2-hydroxyphenyl)butane,    2,2-bis(3,5-di-tert-butyl-4-hydroxyphenyl)prop ane,    2,2-bis-(5-tert-butyl-4-hydroxy2-methylphenyl)-4-n-dodecylmercaptobutane,    1,1,5,5-tetra(5-tert-butyl-4-hydroxy-2-methylphenyl)pentane,    1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene,    1,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6-tetramethylbenzene,    2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)phenol, esters of    β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid with mono- or    polyhydric alcohols, e.g. with methanol, ethanol, n-octanol,    i-octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene    glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol,    diethylene glycol, triethylene glycol, pentaerythritol,    tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide,    3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,    trimethylolpropane,    4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane, esters    of β-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acid with    mono- or polyhydric alcohols, e.g. with methanol, ethanol,    n-octanol, i-octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol,    ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene    glycol, diethylene glycol, triethylene glycol, pentaerythritol,    tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide,    3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,    trimethylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo    [2.2.2] octane;    3,9-bis[2-{3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]    -2,4,8,10-tetraoxaspiro[5.5]- undecane, esters of    β-(3,5-dicyclohexyl-4-hydroxyphenyl)propionic acid with mono- or    polyhydric alcohols, e.g. with methanol, ethanol, octanol,    octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,    1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene    glycol, triethylene glycol, pentaerythritol,    tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide,    3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,    trimethylolpropane,    4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane, esters    of 3,5-di-tert-butyl-4-hydroxyphenyl acetic acid with mono- or    polyhydric alcohols, e.g. with methanol, ethanol, octanol,    octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,    1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene    glycol, triethylene glycol, pentaerythritol,    tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide,    3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,    trimethylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo    [2.2.2] octane; 2) Aminic antioxidants such as    N,N′-di-isopropyl-p-phenylenediamine,    N,N′-di-sec-butyl-p-phenylenediamine,    N,N′-bis(1,4-dimethylpentyl)-p-phenylenediamine,    N,N′-bis(1-ethyl-3methylpentyl)-p-phenylenediamine,    N,N⁷-bis(1-methylheptyl)-p-phenylenediamine,    N,N′-dicyclohexyl-p-phenylenediamine,    N,N′-diphenyl-p-phenylenediamine,    N,N′-bis(2-naphthyl)-p-phenylenediamine,    N-isopropyl-N′-phenyl-p-phenylenediamine,    N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine,    N-(1-methylheptyl)-N′-phenyl-p-phenylenediamine,    N-cyclohexyl-N′-phenyl-p-phenylenediamine,    4-(p-toluenesulfamoyl)diphenylamine,    N,N′-dimethyl-N,N′-di-sec-butyl-p-phenylenediamine, diphenylamine,    N-allyldiphenylamine, 4-isopropoxydiphenylamine,    N-phenyl-1-naphthylamine, N-(4-tert-octylphenyl)-1-naphthylamine,    N-phenyl-2-naphthylamine, octylated diphenylamine, for example    p,p′-di-tert-octyldiphenylamine, 4-n-butyl-aminophenol,    4-butyrylaminophenol, 4-nonanoylaminophenol,    4-dodecanoylaminophenol, 4-octadecanoylaminophenol,    bis(4-methoxyphenyl)amine,    2,6-di-tert-butyl-4-dimethylaminomethylphenol,    2,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane,    N,N,N′,N′-tetra-methyl-4,4′-diaminodiphenylmethane,    1,2-bis[(2-methylphenyl)amino]ethane, 1,2-bis(phenylamino)propane,    (o-tolyl)biguanide, bis[4-(1′,3′-dimethylbutyl)phenyl]amine,    tert-octylated-N-phenyl-1-naphthylamine, a mixture of mono- and    dialkylated tert-butyl/tert-octyldiphenylamines, a mixture of mono-    and dialkylated nonyldiphenylamines, a mixture of mono- and    dialkylated dodecyldiphenylamines, a mixture of mono- and    dialkylated isopropyl/isohexyldiphenylamines, a mixture of mono- and    dialkylated tert-butyldiphenylamines, and the like;-   3) Thiosynergists such as dilauryl thiodipropionate or distearyl    thiodipropionate;-   4) Phosphites and phosphonites such as triphenyl phosphite,    diphenylalkyl phosphites, phenyldialkyl phosphites,    tris(nonylphenyl) phosphite, trilauryl phosphite, trioctadecyl    phosphite, distearylpentaerythritol diphosphite,    tris(2,4-di-tert-butylphenyl) phosphite, diisodecyl pentaerythritol    diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol    diphosphite, bis(2,4-di-cumylphenyl)pentaerythritol diphosphite,    bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite,    diisodecyloxyp entaerythritol diphosphite,    bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritol diphosphite,    bis(2,4,6-tris(tert-butylphenyl)pentaerythritol diphosphite,    tristearyl sorbitol triphosphite, tetrakis(2,4-di-tert-butylphenyl)    4,4′-biphenylene diphosphonite,    6-isooctyloxy-2,4,8,10-tetra-tert-butyl-12H-dibenz [d,    g]-1,3,2-dioxaphosphocin,    bis(2,4-di-tert-butyl-6-methylphenyl)methyl phosphite,    bis(2,4-di-tert-butyl-6-methylphenyl)ethyl phosphite,    6-fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenz[d,g]-1,3,2-dioxaphosphocin,    2,2′,2″-nitrilo-[triethyltris(3,3′,5,5″-tetra-tert-butyl-1,1′-biphenyl-2,2′-diyl)phosphite],    2-ethylhexyl(3,3′,5,5′-tetra-tert-butyl-1,1′-biphenyl-2,2′-diyl)phosphite,    5-butyl-5-ethyl-2-(2,4,6-tri-tert-butylphenoxy)-1,3,2-dioxaphosphirane;-   5) Benzofuranones and indolinones such as those disclosed in U.S.    Pat. No. 4,325,863; 4,338,244; 5,175,312; 5,216,052; 5,252,643;    DE-A-4316611; DE-A-4316622; DE-A-4316876; EP-A-0589839 or    EP-A-0591102, including for example    3-[4-(2-acetoxyethoxy)phenyl]-5,7-di-tert-butylbenzofuran-2-one,    5,7-di-tert-butyl-3-[4-(2-stearoyloxyethoxy)phenyl]-benzofuran-2-one,    3,3′-bis    [5,7-di-tert-butyl-3-(4-[2-hydroxyethoxy]phenyl)benzofuran-2-one],    5,7-di-tert-butyl-3-(4-ethoxyphenyl)b enzofuran- 2-one,    3-(4-acetoxy-3,5-dimethylphenyl)-5, 7-di-tert-butylbenzofuran-2-one,    3-(3,5-dimethyl-4-pivaloyloxyphenyl)-5,7-di-tert-butylbenzofuran-2-one,    3-(3,4-dimethylphenyl)-5,7-di-tert-butylbenzofuran-2-one,    3-(2,3-dimethylphenyl)-5,7-di-tert-burylbenzofuran-2-one, as well    as 6) tocophenols, hydroxylated thiodiphenyl ethers, O—, N— and    S-benzyl compounds, hydroxybenzylated malonates, triazine compounds,    benzylphosphonates, acylaminophenols, amides of    β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, ascorbic acid    (vitamin C), 2-(2′-hydroxyphenyl)benzotriazoles,    2-hydroxybenzophenones, esters of substituted and unsubstituted    benzoic acids, acrylates, nickel compounds, oxamides,    2-(2-hydroxyphenyl)-1,3,5-triazines, hydroxylamines, nitrones,    esters of β-thiodipropionic acid, as described, for example, in U.S.    Pat. No. 6,881,774, incorporated herein by reference.

Preferred antioxidants include:

-   a) mixtures of at least one phenolic compound as described in 1)    above with at least one phosphite or phosphonite compound as    described in 4) above;-   b) mixtures of at least one phenolic compound as described in 1)    above with at least one benzofuranone or indolinone compound as    described in 5) above;-   c) mixtures of at least one phenolic compound as described in 1)    above with at least one aminic antioxidant as described in 2) above;-   d) mixtures of at least one phenolic compound as described in 1)    above with at least one phosphite or phosphonite compound as    described in 4) above and at least one benzofuranone or indolinone    compound as described in 5) above;-   e) mixtures of at least one phenolic compound as described in 1)    above with at least one phosphite or phosphonite compound as    described in 4) above and at least one aminic compound as described    in 2) above;-   f) mixtures of at least one phenolic compound as described in 1)    above with at least one phosphite or phosphonite compound as    described in 4) above, at least one benzofurnanone or indolinone    compound as described in 5) above and at least one aminic compound    as described in 2) above;-   g) mixtures of at least one phenolic compound as described in 1)    above with at least one thiosynergist as described in 3); and-   h) any of mixtures a)-f) above with at least one thiosynergist as    described in 3).

The antioxidant(s), when used, are present in an effective amount, suchas up to about 10 pph. A preferred amount is from 0.1 to 5 pph, and amore preferred amount is from 0.2 to 1.5 pph.

In some embodiments, a HALS (hindered amine light stabilizer) compoundis present. The HALS compound can be used, for example, in conjunctionwith an antioxidant as described in any of 1)-5) above, or inconjunction with any of mixtures a)-h) above.

Suitable HALS compounds includebis(1-octyloxy)-2,2,5,5-tetramethyl-4-piperidinyl) sebacate (Tinuvin™123from BASF),n-butyl-(3,5-di-tert-butyl-4-hydroxylbenzyl)bis-(1,2,2,6-pentamethyl-4-piperidinyl)malonate(Tinuvin™ 144 from BASF), dimethyl 14 CIE180036PCT succinate polymerwith 4-hydroxy-2-2,6,6-tetramethyl-1-piperidinethanol (Tinuvin™ 622 fromBASF), bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate (Tinuvin™ 765from BASF) and bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (Tinuvin™770 from BASF) and the like.

The HALS compound, when used, is present in an effective amount, such asup to about 10 pph. A preferred amount is from 0.1 to 5 pph, and a morepreferred amount is from 0.1 to 2.5 pph.

Other ingredients may be present during the foaming step, including, forexample, fillers, colorants, odor masks, flame retardants, biocides,antistatic agents, thixotropic agents and cell openers.

Polyurethane foam is made in accordance with this invention by forming areaction mixture containing the various ingredients and curing thereaction mixture. Free-rise processes such as continuous slabstockproduction methods can be used. Alternatively, molding methods can beused. Such processes are well known. Generally, no alternation ofconventional processing operations is needed to produce polyurethanefoam in accordance with this invention (other than the inclusion of theacetoacetate ester and/or amide, the aminoalcohol and/oralkylhydroxylamine and optionally the antioxidant(s) and/or HALScompound).

The various ingredients may be introduced individually or in varioussubcombinations into a mixhead or other mixing device where they aremixed and dispensed into a region (such as a trough or other opencontainer, or a closed mold) where they are cured. It is oftenconvenient, especially when making molded foam, to form a formulatedpolyol component that contains the isocyanate-reactive compound(s),including crosslinkers and/or chain extenders as may be used, theacetoacetate ester and/or amide, aminoalcohol and/or alkylhydroxylamine,alkali metal hydrogen sulfite, the antioxidant(s) and HALS compounds (ifany), and optionally the catalyst(s), surfactant(s) and blowingagent(s). This formulated polyol component is then contacted with thepolyisocyanate (as well as any other ingredients that are not present inthe formulated polyol component) to produce the foam.

Some or all of the various components may be heated prior to mixing themto form the reaction mixture. In other cases, the components are mixedat approximately ambient temperatures (such as from 15-40° C.). Heat maybe applied to the reaction mixture after all ingredients have beenmixed, but this is often unnecessary.

The product of the curing reaction is a flexible polyurethane foam. Thefoam density may be from 20 to 200 kg/m³. For most seating and beddingapplications, a preferred density is from 24 to 80 kg/m³. The foam mayhave a resiliency of at least 50% on the ball rebound test of ASTM3574-H. Foams produced in accordance with this invention are useful, forexample, in cushioning applications such as bedding and domestic, officeor vehicular seating, as well as in other vehicular applications such asheadrests, dashboards instrument panels, armrests or headliners.

Polyurethane foams made in accordance with the invention arecharacterized in having reduced emissions formaldehyde, acetaldehyde andpropionaldehyde compared to the case in which the acetoacetate esterand/or amide and aminoalcohol and/or alkylhydroxylamine are absent. Asuitable method for measuring formaldehyde, acetaldehyde andpropionaldehyde emissions is as follows: The polyurethane foam sample iscrushed to open the cells. The crushed foam is cut into cubic 30 gramsamples, which are immediately packaged tightly in aluminum foil orpolyethylene film and kept in this is manner for 5 days at about 25° C.

Aldehyde concentrations are measured according to the Toyota TSM0508Gtest method. In that Toyota method, the foam sample is removed from thefoil or film and then placed in individual 10 L Tedlar gas bags (DelinCo., Ltd., China) that has previously been purged three times withnitrogen gas. The bag with the foam sample is filled with 7 L ofnitrogen, sealed and heated 65° C. for two hours. The plastic bagcontaining the foams is removed from the oven. The gas in the bag ispumped through a 350 mg dinitrophenylhydrazine cartridge to capture thecarbonyl compounds. The captured carbonyl compounds are analyzed forformaldehyde, acetaldehyde and propionaldehyde by liquid chromatography,with results being expressed in terms of weight of the respectivealdehyde per cubic meter of gas in the gas bag. Details for a specificmethod of performing the Toyota method are described in the followingexamples.

The amount of emitted formaldehyde, acetaldehyde and propionaldehyde asdetermined in this method are all typically at least 20%, usually atleast 50%, and sometimes as much as 80 to 98%, reduced as compared to anotherwise like foam that is produced in the absence of the acetoacetateester and/or amide and aminoalcohol and/or alkylhydroxylamine. Anadvantage of this invention is that significant reductions are seen inthe emitted amounts of all three of these aldehyde compounds.

In some embodiments, the amount of emitted formaldehyde is no greaterthan 10 μg/m³ or no greater than 5 μg/m³, as measured according to theToyota method. In some embodiments, the amount of emitted acetaldehydeis no greater than 200 μg/m³, as measured according to Toyota method. Insome embodiments, the amount of emitted s propionaldehyde is no greaterthan 100 μg/m³ or no greater than 60 μg/m³, as measured according to theToyota method. The sum of emitted amounts of formaldehyde, acetaldehyde,acrolein and propionaldehyde in some embodiments is no greater than 250μg/m³, as measured according to the Toyota method.

The following examples are provided to illustrate the invention, but arenot intended to limit the scope thereof. All parts and percentages areby weight unless otherwise indicated.

EXAMPLE 1 AND COMPARATIVE SAMPLES A-C

Formulated Polyol A is made by combining 45.34 parts of aglycerin-initiated polypropylene oxide) capped with 15 percent ethyleneoxide and having a hydroxyl number of 27.5 mg KOH/g; 50.11 parts of acopolymer polyol having a hydroxyl number of 22 mg KOH/g and containing40 percent by weight copolymerized styrene and acrylonitrile solidsdispersed in a polyether polyol; 0.48 part of diethanolamine, 0.38 partof glycerine, 0.27 part of a 33 percent triethylene diamine indipropylene glycol, 0.17 part of a tertiary amine/glycol mixtureavailable as C225 from Momentive Co., Ltd.; 1.15 parts of anorganosilicone foam-stabilizing surfactant and 2.1 parts of water.

Formulated Polyol B is made by combining 100 parts of Formulated PolyolA with 0.5 part of benzenepropanoic acid, 3,5-bis(1,1-dimethyl-ethyl)-4-hydroxy-C7-C9 branched alkyl esters (available asIRGANOX™ 1135 antioxidant from BASF (China) Co., Ltd) and 0.1 part of1,1,1-tris (hydroxymethyl) methylamine in a high speed laboratory mixer.

Formulated Polyol C is made by combining 100 parts of Formulated PolyolA with 0.5 part of benzenepropanoic acid, 3,5-bis(1,1-dimethyl-ethyl)-4-hydroxy-C7-C9 branched alkyl esters (available asIRGANOX™ 1135 antioxidant from BASF (China) Co., Ltd) and 0.1 parts ofAcAcNHPH in a high speed laboratory mixer. Formulated Polyol 1 is madeby combining 100 parts of Formulated Polyol A with 0.5 part of IRGANOX™1135, 0.1 part of AcAcNHPh, and 0.07 part of 1,1,1-tris (hydroxymethyl)methylamine in a high speed laboratory mixer.

Each of Formulated Polyols A, B, C and 1 are stored at room temperaturefor 12-24 hours before being processed into a foam.

Comparative Sample A is made by combining 100 parts of Formulated PolyolA with 28 parts of a 20/80 by weight blend of toluene diisocyanate (TDI)and methylene diphenyldiisocyanate (MDI), pouring the resulting reactionmixture into a cup and allowing the reaction mixture to rise and cure toform a polyurethane foam. After the foam has cured enough to bedimensionally stable, it is removed from the cup and 30 gram samplecubes are cut. The foam cubes each are immediately wrapped in aluminumfoil to form an air-tight package for 7 days.

Comparative Sample B is made in the same manner, except 100 parts ofFormulated

Polyol B are combined with 28 parts of the same TDI/MDI blend.Comparative Sample C is made in the same manner, except 100 parts ofFormulated Polyol C are combined with 28 parts of the same TDI/MDIblend.

Example 1 is made in the same manner, except 100 parts of FormulatedPolyol 1 are combined with 28 parts of the same TDI/MDI blend.

Aldehydes emitted from the foam samples are analyzed using the Toyotagas bag method. The cubed foam samples are in each case removed from thefoil and put into a 10 L Tedlar gas bag that has been washed with purenitrogen three times and emptied. An empty gas bag is used as a blank.After the foam sample is put into the gas bag, the bag is filled withabout 7L of nitrogen gas and heated in the oven for 2 hours at 65° C.The nitrogen gas in the gas bag is then pumped out by an air pump andanalyzed for formaldehyde, acetaldehyde and propionaldehyde.

The gas from each bag is passed through a dinitrophenylhydrazine (DNPH)cartridge (CNWBOND DNPH-Silica cartridge, 350 mg, Cat. No. SEEQ-144102,Anple Co., Ltd.) at a sampling speed is 330 mL/min. The aldehydesemitted from the foam into the gas are absorbed by the cartridge to formDNPH derivatives. The DNPH cartridge is eluted with 3 g of acetonitrile,and the resulting acetonitrile solution is analyzed by HPLC to quantifythe carbonyls in the sample, as follows.

A standard solution containing 15 μg/mL each of formaldehyde,acetaldehyde and propionaldehyde (in each case in the form of DNPHderivatives) (TO11A carbonyl-DNPH mix, Cat. No. 48149-U, Supelco Co.,Ltd) is diluted with acetonitrile. A vial containing 2 mL of the dilutedsolution (containing 0.794 ppm of each of formaldehyde, acetaldehyde andpropionaldehyde) is refrigerated to −4° C. The refrigerated solution isinjected into the HPLC system and analyzed for formaldehyde,acetaldehyde and propionaldehyde derivatives. The response factor iscalculated from the area of the elution peak for each derivative,according the formula:

${{Response}\mspace{14mu} {factor}\mspace{14mu} i} = \frac{{Peak}\mspace{14mu} {Area}\mspace{14mu} i}{0.794}$

where Response factor i=Response factor of derivative i; Peak Areai=Peak Area of derivative i in standard solution and 0.794=theconcentration of each derivative in the standard solution.

The amount of formaldehyde, acetaldehyde and propionaldehyde emitted byeach of Comparative Samples A and B and Example 1 are then determined.In each case, the acetonitrile solution obtained by eluting the DNPHcolumn is injected into the HPLC system and the area of the elution peakis determined from each derivative. The concentration of thealdehyde-DNPH derivative in the sample solution is calculated asfollows:

${{Concentration}\mspace{14mu} {of}\mspace{14mu} i} = \frac{{Peak}\mspace{14mu} {Area}\mspace{14mu} i}{{Response}\mspace{14mu} {factor}\mspace{14mu} i}$

where: Concentration of i=Concentration of aldehyde—DNPH derivative inthe sample solution, Peak Area i=Peak Area of Derivative i in samplesolution and Response factor i=Response factor of derivative i,determined from the standard solutions as described above.

The HPLC conditions are as follows:

Instrument: Agilent 1200 HPLC Column: Supelco Ascentis Express C18, 15cm*4.6 mm, 2.7 um Mobile Phase: Solvent A: 0.1% H₃PO₄ in AcetonitrileSolvent B: 0.1% H₃PO₄ in DI water Column Oven: 15° C. Detection: DADdetector at 360 nm Time (mn) % A % B Flow (mL/min) Gradient: 0 45 55 1 745 55 1 14 50 50 1 20 85 15 1 25 100 0 1 Equilibration Time: 5 minInjection: 10 uL

The concentrations of formaldehyde, acetaldehyde and propionaldehyde foreach of Comparative Samples A-C and Example 1 are as indicated in Table1.

TABLE 1 Comp. A* Comp. B* Comp. C* Ex. 1 Additives None 0.5% IRGANOX1135. 0.5% IRGANOX 1135. 0.5% IRGANOX 1135. 0.1% 1,1,1- 0.1% AcAcNHPh0.07% 1,1,1- tris(hydroxymethyl) tris(hydroxymethyl) methylaminemethylamine 0.1% AcAcNHPH Formaldehyde, 38 34 21 20 μg/m³ Acetaldehyde,156 128 112 120 μg/m³ Propionaldehyde, 178 114 146 129 μg/m³ Total 372276 279 269 Aldehydes, μg/m³ *Not an example of this invention.

Adding the antioxidant and 1,1,1-tris(hydroxymethyl) methylamine intothe foam formulation (Comp. B) results in little or no reduction in theamount of emitted formaldehyde, and modest reductions in the emittedamounts of each of acetaldehyde and propionaldehyde.

Adding the antioxidant and AcAcNHPh leads to a substantial (about 45%)decrease in formaldehyde emissions but only a modest decrease inacetaldehyde emissions and only a small reduction in propionaldehydeemissions.

Example 1, by contrast, exhibits a reduction in emitted formaldehyde ofabout 50% and significant reductions in each of acetaldehyde andpropionaldehyde emissions. Total emitted aldehyde emissions are lowerthan any of the Comparative Samples.

EXAMPLE 2-3 AND COMPARATIVE SAMPLES D-G

Formulated Polyol D is a commercially available formulated polyol thatcontains a mixture of polyols having a functionality of at least 2 andan equivalent weight of at least 200; urethane catalysts, water andsurfactant.

Formulated Polyol E is made by combining 100 parts of Formulated PolyolD with 0.5 part IRGANOX™ 1135 antioxidant and 0.1 part of1,1,1-tris(hydroxymethyl) methylamine in a high speed laboratory mixer.

Formulated Polyol F is made by combining 100 parts of Formulated PolyolD with 0.5 part IRGANOX™ 1135 antioxidant and 0.05 part of1,1,1-tris(hydroxymethyl) methylamine in a high speed laboratory mixer.

Formulated Polyol G is made by combining 100 parts of Formulated PolyolD with 0.5 part IRGANOX™ 1135 antioxidant and 0.1 part oftrimethylolpropane triacetoacetate (AATMP) in a high speed laboratorymixer.

Formulated Polyol 2 is made by combining 100 parts of Formulated PolyolD with 0.5 part IRGANOX™ 1135 antioxidant, 0.1 part of 1,1,1-tris(hydroxymethyl) methylamine and 0.1 parts of AATMP in a high speedlaboratory mixer.

Formulated Polyol 3 is made by combining 100 parts of Formulated PolyolD with 0.5 part IRGANOX™ 1135 antioxidant, 0.05 part of 1,1,1-tris(hydroxymethyl) methylamine and 0.1 parts of AATMP in a high speedlaboratory mixer.

Comparative Samples D-G and Examples 2-3 each are formed intopolyurethane cup foams and tested, in the manner described in theprevious examples. Results are as indicated in Table 2.

TABLE 2 Comp. D* Comp. E* Comp. F* Comp. G* Ex. 2 Ex. 3 Additives AO¹,pph 0 0.5 0.5 0.5 0.5 0.5 1,1,1-Tris², pph 0 0.1 0.05 0 0.1 0.05 AATMP³,pph 0 0 0 0.1 0.1 0.1 Test Results Formaldehyde, 87 86 72 10 4 4 μg/m³Acetaldehyde, 298 193 223 192 180 182 μg/m³ Propionaldehyde, 87 61 59 9654 65 μg/m³ Total Aldehydes, 472 330 354 298 238 251 μg/m³ *Not anexample of this invention. ¹Antioxidant.²1,1,1-tris(hydroxylmethyl)methylamine. ³Trimethylolpropanetriacetoacetate.

As the data in Table 3 shows, the combination of antioxidant,aminoalcohol and AATMP results in the greatest reduction of aldehydeemissions.

Example 3 and Comparative Samples D-F are repeated, except this time thefoams are produced in a closed mold. Results of the aldehydemeasurements are indicated in Table 3, indicated in this case as totalmeasured emissions from the test sample in micrograms.

TABLE 3 Comp. D* Comp. E* Comp. F* Ex. 3 Additives AO¹, pph 0 0.5 0.50.5 1,1,1-Tris², pph 0 0.1 0.05 0.05 AATMP³, pph 0 0 0 0.1 Test ResultsFormaldehyde, 0.39 0.36 0.43 0.08 μg/test piece Acetaldehyde, 1.81 0.801.04 1.04 μg/test piece Propionaldehyde, 0.47 0.27 0.31 0.34 μg/testpiece Total Aldehydes, 2.67 1.43 1.79 1.46 μg/test piece *Not an exampleof this invention. ¹Antioxidant. ²1,1,1-tris(hydroxylmethyl)methylamine.³Trimethylolpropane triacetoacetate.

Large reductions in the emitted quantities of all three aldehydes areagain seen with the invention, compared with the control. Formaldehydein particular is reduced to a very low level without sacrificingreductions in the other aldehyde emissions.

EXAMPLE 4 AND COMPARATIVE SAMPLES H-J

Formulated Polyol H is a commercially available formulated polyol thatcontains a mixture of polyols having a functionality of at least 2 andan equivalent weight of at least 200; urethane catalysts, water andsurfactant.

Formulated Polyol I is made by combining 100 parts of Formulated PolyolH with 0.5 part IRGANOX™ 1135 antioxidant and 0.05 part of1,1,1-tris(hydroxymethyl) methylamine in a high speed laboratory mixer.

Formulated Polyol J is made by combining 100 parts of Formulated PolyolH with 0.5 part IRGANOX™ 1135 antioxidant and 0.05 part of AATMP in ahigh speed laboratory mixer.

Formulated Polyol 4 is made by combining 100 parts of Formulated PolyolJ with 0.5 part IRGANOX™ 1135 antioxidant, 0.05 part of 1,1,1-tris(hydroxymethyl) methylamine and 0.05 part of AATMP in a high speedlaboratory mixer.

Comparative Samples H, I and J and Example 4 each are formed intopolyurethane cup foams and tested, in the manner described in theprevious example. Results are as indicated in Table 4.

TABLE 4 Comp. H* Comp. I* Comp. J* Ex. 4 Additives AO¹, pph 0 0.5 0.50.5 1,1,1-Tris², pph 0 0.05 0 0.05 AATMP³, pph 0 0 0.05 0.05 TestResults Formaldehyde, 78 75 51 43 μg/test piece Acetaldehyde, 233 189234 178 μg/m³ Propionaldehyde, 104 79 107 74 μg/m³ Total Aldehydes, 415343 392 296 μg/m³ *Not an example of this invention. ¹Antioxidant.²1,1,1-tris(hydroxylmethyl)methylamine. ³Trimethylolpropanetriacetoacetate.

As the data in Table 4 shows, the combination of aminoalcohol and AATMPleads to the greatest reduction in the amount of all three emittedaldehydes and the lowest level of total aldehyde emissions.

1. A process for producing a polyurethane foam comprising forming areaction mixture that contains an aromatic polyisocyanate, at least oneisocyanate-reactive material having an average functionality of at least2 and an equivalent weight of at least 200 per isocyanate-reactivegroup, at least one blowing agent, at least one surfactant and at leastone catalyst, and curing the reaction mixture in the presence of (i) atleast one acetoacetate ester or amide and (ii) at least one aminoalcoholand/or alkylhydroxylamine to form the polyurethane foam.
 2. A method forreducing aldehyde emissions from a polyurethane foam, comprising: a)combining (i) at least one acetoacetate ester or amide and, (ii) atleast one aminoalcohol and/or alkylhydroxylamine with at least oneisocyanate-reactive material having an average functionality of at least2 and an equivalent weight of at least 200 per isocyanate-reactive groupto form a mixture and then b) combining the mixture from step a) with atleast one organic polyisocyanate and curing the resulting reactionmixture in the presence of at least one blowing agent, at least onesurfactant and at least one catalyst to form a polyurethane foam.
 3. Theprocess of claim 1 wherein the acetoacetate ester or amide isrepresented by structure II:

wherein A is a linking group, n is at least 1, R¹ is a substituted orunsubstituted C₁-C₆ alkyl or a substituted or unsubstituted aryl groupand X is —O— in the case of an ester and —NH—, in the case of an amide.The process of claim 1 wherein the acetoacetate ester or amide is one ormore of trimethylolpropane mono-, di or triacetoacetate ester,trimethylolethane mono- di- or tri acetoacetate ester, trimethoxymethanemono-, di- or triacetoacetate ester; ethylene glycol mono- ordiacetoacetate ester; 1,2-propylene glycol mono- or diacetoacetateester, 1,3-propylene glycol mono- or diacetoacetate ester,pentaerythritol mono-, di-, tri- or tetraacetoacetate ester, glycerinmono-, di or triacetoacetate ester, diethylene glycol mono- ordiacetoacetate ester, dipropylene glycol mono- or diacetoacetate ester,triethylene glycol mono- or diacetoacetate ester, erythritol mono-, di-,tri- or tetraacetoacetate ester, n-hexane mono-, di, tri, tetra, penta-,or hexaacetoacetate ester, sorbitol mono-, di-, tri-,tetra-, penta- orhexaacetoacetate ester and 1,4-butanediol mono- or diacetoacetate ester.5. The method of claim 1 wherein the aminoalcohol or alkylhydroxylamineis represented by structure (I):

or a salt of such a compound, wherein R⁶, R⁷ and R⁸ each areindependently H, alkyl optionally substituted with phenyl or NR⁹and R¹⁰wherein R⁹ and R¹⁰ are independently H, C₁-C₆ alkyl or phenyl, orhydroxyalkyl optionally independently substituted with phenyl or NR⁹R¹⁰and R⁵ is H, hydroxyl, phenyl, alkyl optionally substituted with phenylor NR⁹R¹⁰, or hydroxyalkyl optionally independently substituted withphenyl or NR⁹R¹⁰, provided that when none of R⁶, R⁷ and R⁸ arehydroxyalkyl, then R⁵ is hydroxyl or hydroxyalkyl optionallyindependently substituted with phenyl or NR⁹R¹⁰ .
 6. The method of claim1 wherein the aminoalcohol or alkylhydroxylamine is selected from one ormore of 2-amino-1-butanol, 2-amino-2-ethyl-1,3-propanediol,2-amino-2-methyl-1-propanol, 2-amino-1-methyl-1,3-propanediol,1,1,1-tris (hydroxymethyl) methylamine, ethanolamine, diethanolamine,N-methylethanolamine, N-butylethanolamine, monoisopropanolamine,2-amino-2 (hydroxymethyl)prop ane- 1,3-diol. diisopropanolamine,mono-sec-butanolamine, di-sec-butanolamine, N-isopropylhydroxylamine,ethylhydroxylamine, methylhydroxylamine, N-butylhydroxylamine andsec-butylhydroxylamine.
 7. The method of claim 1 wherein theacetoacetate ester or amide is present in an amount of from 0.02 to 0.25parts by weight per 100 parts by weight of the at least one isocyanatereactive compound having at least two isocyanate-reactive groups permolecule and an equivalent weight of at least 200 perisocyanate-reactive group.
 8. The method of claim 1 wherein theaminoalcohol or alkylhydroxylamine compound is present in an amount offrom 0.05 to 0.25 parts by weight per 100 parts by weight of the atleast one isocyanate reactive compound having at least twoisocyanate-reactive groups per molecule and an equivalent weight of atleast 200 per isocyanate-reactive group.
 9. The method of claim 1wherein the reaction mixture is cured in the presence of an antioxidant.10. The method of claim 9 wherein the antioxidant is a phenoliccompound.
 11. The method of claim 10 wherein the antioxidant is presentin an amount of 0.2 to 1.5 parts by weight per 100 parts by weight ofthe at least one isocyanate reactive compound having at least twoisocyanate-reactive groups per molecule and an equivalent weight of atleast 200 per isocyanate-reactive group.
 12. The method of claim 1wherein the acetoacetate ester or amine is trimethylolpropanetriacetoacetate.
 13. The method of claim 12 wherein the aminoalcohol oralkylhydroxylamine is 1,1,1 tris(hydroxymethyl) methylamine.
 14. Apolyurethane foam made in accordance with the process of claim 1.